gpsdecode is a utility that can decode GPS, RTCM or AIS streams into a readable format, in particular json.
⏰ But it does not manage tag blocks and in some cases, it is interesting to load the timestamps of certain messages that are only present in the tag blocks.
This project proposes a solution to load the timestamp obtained from the block c tag from AIS content, into a timestamp property in the json output.
😎 As a result, you can use docker to quickly get this structured data with an ISO 8601 timestamp:
{"class":"AIS","device":"stdin","type":1,"repeat":0,"mmsi":219164000,"scaled":true,"status":0,"status_text":"Under way using engine","turn":0,"speed":10.0,"accuracy":false,"lon":10.825043,"lat":57.027050,"course":152.1,"heading":153,"second":28,"maneuver":0,"raim":false,"radio":49355,"timestamp":"2024-12-10T09:00:27+0000"}Build docker image:
docker build . -t gpsd-timestampSome examples:
# Analyze a TCP socket (Norwegian Coastal Administration)
docker run -it --rm \
--mount type=tmpfs,destination=/tagblocks \
-e AIS_HOSTNAME="153.44.253.27" -e AIS_PORT=5631 \
gpsd-timestamp
# File with bind mount
docker run -it --rm --entrypoint="" \
--mount type=tmpfs,destination=/tagblocks \
-v ${PWD}/data/norwegian.raw:/data.raw -e AIS_FILE=/data.raw \
gpsd-timestamp
# Standard input from file
docker run -i --rm \
--mount type=tmpfs,destination=/tagblocks \
gpsd-timestamp < data/norwegian.raw
# Standard input from command's pipe, here a socket reading
nc 153.44.253.27 5631 | docker run -i --rm \
--mount type=tmpfs,destination=/tagblocks \
gpsd-timestamp
# Standard input from command's pipe, here reading from a tgz
# For memory, compression: tar --directory=data -cvzf data/norwegian.raw.tgz norwegian.raw
tar -xOzf data/norwegian.raw.tgz norwegian.raw | docker run -i --rm \
--mount type=tmpfs,destination=/tagblocks \
gpsd-timestampNote: at runtime, speed up with --mount type=tmpfs,destination=/tagblocks